Sites of synthesis and release of PBAN-like factor in the female European corn borer, Ostrinia nubilalis

Abstract

Sex-pheromone production in female European corn borer moths, Ostrinia nubilalis, is regulated by PBAN(pheromone biosynthesis activating neuropeptide)-like factors. Using a decapitated-moth bioassay, three discrete sets of neurosecretory cells were identified in the subesophageal ganglion of female O. nubilalis that contained PBAN-like biological activity. Immunocytochemical studies with a polyclonal antiserum raised against a synthetic-truncated Hez-PBAN revealed the presence of PBAN-like immunoreactivity throughout the entire ventral nervous system. The corpora cardiaca also exhibited PBAN-like biological activity and immunoreactivity. Corpora cardiacectomized-allatectomized females produced significantly less pheromone than sham-operated females. Cobalt anterograde/retrograde filling studies did not show direct neural connections between the terminal abdominal ganglion and the sex-pheromone gland. Transection of the ventral nerve cord did not impair pheromone production. Removal of the entire abdominal ventral nerve cord did not affect the response of the operated females to exogenous PBAN. Results of the present investigation show that PBAN-like factors in female O. nubilalis moth are synthesized in three sets of neurosecretory cells in the subesophageal ganglion, and that release of these factors from the corpora cardiaca plays a more important role in pheromone production than does the ventral nerve cord.